"Surprising" Phenomenon
When a babbler spots a predator, that babbler and its group make loud, barklike calls despite the fact that the loud noise itself is typically the reason why the predator discovers that the birds are there.
Objective
The right answer will be a hypothesis that explains why babblers make their barklike call in response to predator sightings even though the call is often what draws their predator’s attention. That explanation will either describe some survival benefit of the barklike call which could outweigh the risks, or a way in which alerting predators of their presence is beneficial to the babblers’ chances of survival.
A
Babblers fly much faster than the predators that prey upon them.
While this answer might explain a way by which babblers escape their predators, it does nothing to explain why the birds would make a noise that alerts the predators to their presence in the first place.
B
Babblers’ predators are generally intimidated by large numbers of babblers.
This explains why it might be a good idea for babblers to make noise when predators are near. Predators are intimidated by large numbers of babblers, and only by hearing their collective call do predators become aware that there are many babblers nearby.
C
There is more than one type of predator that preys upon babblers.
The fact that there are multiple types of predators preying on babblers does nothing to explain why the babblers would want to call any predator’s attention to their presence.
D
Babblers’ predators have very good eyesight but relatively weak hearing.
This may seem to mitigate the potential damage of the babblers’ loud call—maybe the predators can’t hear them well anyway?—but it does nothing to explain why the babblers would want to make any noise at all in the presence of predators.
E
Animals that live in close proximity to babblers are also preyed upon by the predators that prey upon babblers.
Even if the babblers’ call tells predators that other prey are nearby, it still also proves that the babblers themselves are there. Predators could easily decide to eat the babblers instead of the other animals, and this answer doesn’t explain why babblers would take that risk.
Summarize Argument
The author concludes that an outbreak of tree-eating tussock moths in a forest should not be countered in most of the forest. The author supports the conclusion by claiming that the tree-eating moths could be good for the forest in areas with too many immature trees. The question stem then asks us to fill in a missing premise to further support the conclusion.
Notable Assumptions
The author assumes that the possible benefits of moths described in the argument will apply in most of the forest—in other words, that most of the forest is crowded with immature trees. The author also assumes that the moths will not have a greater detrimental effect compared to their beneficial effect.
A
more than half of the forest is unnaturally crowded with immature trees
This strengthens by affirming the author’s assumption that the beneficial effects of the moth will affect most of the forest, since the problem of overcrowding that the tree-eating moths can help solve does affect more than half the forest.
B
mature trees are usually the first to be eaten by tussock moths
This weakens by undermining the author’s assumption that the benefits of the moths will outweigh any detrimental effects. Moths that prefer mature trees would do more harm by eating the healthy, mature trees of the forest than benefit by eating the overcrowded, immature trees.
C
usually a higher proportion of mature trees than of immature ones are destroyed in forest fires
This is irrelevant. First, the author has already established that a lack of forest fires still results in overcrowding of immature trees. Second, we don’t care what forest fires do—that’s just not what the argument is about, and we don’t know if this forest even had a fire.
D
the expected outbreak of tussock moths will almost certainly occur if no attempt is made to counter it
This is irrelevant, since we already know that not countering the outbreak will result in the outbreak occurring—we care about whether or not that’s a good thing.
E
there are no completely effective countermeasures against the moth
This is irrelevant to the author’s argument that the outbreak should not be countered in any way in most of the forest, regardless of whether fully effective countermeasures exist or not.
Summarize Argument
A lack of funds for research hurts the ability of universities to fulfill their primary purpose. How? The university’s purpose is to educate. To be strong educators, professors must know about new developments, which requires research. However, many universities don’t have enough funds to properly support research. This, in turn, hurts universities ability to educate.
Identify Conclusion
The conclusion is the author’s claim about university education: “a lack of funds for research adversely affects the degree to which a university can fulfill its central mission.”
A
In order to be able to teach well, university professors must conduct research.
This is part of the reasoning that links a lack of funds to the inability of a university to fully complete its central mission of education.
B
Lack of financial support for faculty research is the root of ineffective teaching at universities.
This goes too far. The stimulus says that professors need research to teach well, but does not go so far as to say a lack of support for research is the ultimate cause of ineffective teaching.
C
Effective teaching is the primary mission of a university.
This is context that lets us know that the central mission discussed in the conclusion is to educate.
D
Lack of funds for research reduces the quality of education a university provides.
This accurately rephrases the conclusion. The argument is set up to show that a lack of funds hurt’s the university’s central mission: education.
E
New means of funding faculty research at universities are needed.
The conclusion is simply stating that a lack of funds has a certain negative effect. It does not go so far as to suggest a solution, as this answer choice does.